This invention relates to the use of sheet materials with reciprocating head machines, particularly in ultrasonic welding.
In many industrial processes sheets of materials are used with reciprocating head machines, for example, those in which a head moves along a prescribed path into and out of engagement with one or more work pieces.
Thus, in ultrasonic welding a movable head or "horn" is moved into translational engagement with work pieces which are joined together by virtue of the vibratory energy transmitted from the horn to the parts. The vibratory energy is termed "ultrasonic" because it is either at the high end or beyond the audible sound spectrum.
For many materials, the contact of the horn with the work pieces can produce an undesirable marking. The marking is particularly objectionable where parts are being welded to produce a finished product. Even where the marking is easily removed, it is objectionable because of the need for an additional cleaning operation before the ultrasonically welded parts are ready for shipment.
It has been discovered that the marking of ultrasonically welded parts can be avoided by the interposition of a thin sheet or film of polyethelene between the parts being welded and the head. The film, which is on the order one to ten mills in thickness serves as a cushion for the head and avoids marking the parts. In one technique for using such a film to avoid marking, the operator manually positions the sheet of polyethelene between the welding head and the part before the head is brought into welding engagement. This procedure not only is subject to erratic operator manipulation, it also is accompanied by operator fatigue and it makes inefficient use of the cushioning material.
Accordingly, it is an object of the invention to facilitate the use of sheets of material with work being processed. A related object is to facilitate the use of thin sheets of material with reciprocating head machines. Another related object is to facilitate the use of thin sheets of material in ultrasonic welding and hot stamp processing.
Another object of the invention is to avoid interference with work pieces by thin sheets of material used in conjunction with reciprocating head machines. A related object is to avoid work piece interference by thin sheets of material in ultrasonic welding and hot stamp processing.
Still another object of the invention is to limit operator fatigue and interference with the operator work area in the use of thin sheets of material with respect to a work piece. A related object is to avoid operator fatigue and work area interference by thin sheets of material in ultrasonic welding, as well as in hot stamp processing.